The overarching goal of this research proposal is to better understand how the bilingual adult brain comprehends language in real time. These studies address the prediction, access and subsequent integration of words into context during language comprehension. We use a direct measure of real time brain activity -- event-related potentials (ERPs) -- in both monolingual and bilingual populations. In a subset of experiments we use a grammatical feature present in over half the world's languages -- morphosyntactic gender -- as a tool toward this goal. In the first aim, expectations about words will be analyzed by comparing ERP responses of native Spanish speakers, Spanish-English bilinguals, and French-English bilinguals, while reading words and sentences in the presence or absence of language switching. The way gender is used during predictive processes is expected to vary based on the nature of the language environment (e.g., language switching or not) and the statistical properties of gender in a specific language. The second aim will focus on the timing of word access and integration in each language of Spanish-English bilinguals. In the first experiment fluent bilinguals will read sentences that have a word that makes sense or not, and creates a language switch or not. The effect of semantic anomalies should vary as a function of switching and language dominance. The second experiment uses a bilingual color-Stroop paradigm to test lexical access in both languages of fluent bilinguals. Within and cross-language interference should vary as a function of language dominance. The third experiment will compare grammatical processes in sentence comprehension between bilinguals in early and later stages of learning their second language. This study tests the effect of proficiency on meaning and grammar processes in a first and second language to determine if meaning and structure are affected differently by language ability. In sum, this project will examine meaning and grammar at both the word and sentence levels of processing in one or more languages. Ultimately, this research will contribute to our understanding of the structure and timing of how the brain -- mono- or multi-lingual -- comprehends language in real time. The main developmental objectives of this grant proposal are for the PI to obtain funding on an independent R01 or equivalent grant by the fifth year of funding, and to continue to contribute significant work in cognitive neuroscience and bilingualism.